trilemma

1. (logic) An argument containing three alternatives, jointly exhaustive either under any condition(s) or under all condition(s) consistent with the universe of discourse of that argument, that each imply the same conclusion.Examples: "It has been remarked as a characteristic of the late Sir Robert Peel, that in introducing his measures to the House of Commons, he often used the trilemma. "Three courses are before us—to go backward, to stand still, to go forward. We cannot go backward; we cannot stand still; we must, then, go forward.""; "And in anticipation of it, while he [Johann Joseph Ignaz von Döllinger] declares at one moment that it would be profane to limit Divine Providence to an alternative, he affirms in the next that there can be no harm whatever in shutting it up to a supposed exhaustive trilemma."